1. Field of the Invention
The present invention relates to a steering system for an outboard motor, the steering system generating steering force by an electric motor.
2. Description of the Related Art
Small watercraft fitted with outboard motors typically include a steering wheel to provide steering input for the motor. A steering system can translate steering wheel inputs into movement of the motor for steering the watercraft.
As shown in FIGS. 8 and 9, one conventional steering system employs a drive mechanism 50 formed with a rack and pinion unit, each with an electric motor, for an outboard motor (see also Japanese Publication No. 04-038297). An electric motor 51 is used as a driving power source generating rotational power of a pinion of the unit. A guide plate 52 moving linearly in a transverse direction together with the pinion has a slot 53 extending in a fore to aft direction. A guide pin 56 is disposed at an end of a steering bracket 55 fixed to an outboard motor body 54 and extending horizontally. A link mechanism 57 is formed with the guide plate 52 and the guide pin 56 in such a manner that the guide pin 56 is slidably fitted into the slot 53 of the guide plate 52. The pinion moves over a rack of the unit to convert the linear movement of the pinion to the pivotal movement of the steering bracket 55 via the link mechanism 57. The pivotal movement of the steering bracket 55 steers the outboard motor body 54.
The conventional steering system for an outboard motor is arranged so that: a clamping bracket 58 mounts the outboard motor body 54 to a transom board 60 of the watercraft 59. The outboard motor body 54 is allowed to pivot rightward or leftward in a horizontal plane about an axis of a swivel shaft (not shown) pivotally carried by a swivel bracket 61 fixed to the outboard motor body 54. Thereby, a forward direction of the watercraft 59 is decided.
However, in such a conventional steering system for an outboard motor, the drive mechanism 50 including the electric motor 51 and the rack and pinion unit is attached to the watercraft at a location adjacent to a tilt shaft 63 positioned in front of the clamping bracket 58 that couples the outboard motor 62 to the transom board 60. The drive mechanism 50 is positioned generally inside of the watercraft 59, and room adjacent the transom 60 is needed to accommodate this mechanism. Also, the clamping bracket 58 needs an aperture for attachment. Furthermore, the outboard must carry the steering bracket 55. Such a construction makes the whole structure complicated and also makes the combined clamping bracket 58 and drive mechanism 50 voluminous. Also, attaching the steering system thus may prove to be troublesome. In addition, the steering system can occupy a large space around the clamping bracket 58 within the watercraft 59 to prevent the system from interfering with other components when the outboard motor body 54 is tilted up.